It is well documented that African-American women with breast cancer are more likely to have a more aggressive type of the disease that kills them, but why remains a mystery.

The answers may be found one day soon, as researchers focus more on the genetic makeup of cancer tumors and how African-American women may respond differently to treatment than women of other races.

"There are two different tracks of research going on that could in the future help better treat African-American women with breast cancer," said Rebecca McCoy, community health director of the advocacy group Komen Maryland.

While African-American women are less likely to get breast cancer than white women, they have a higher death rate from the disease. It is the second most common cause of cancer death among African-American women, killing more than 6,000 nationwide last year.

Some of this may be attributed to the fact that African-Americans are diagnosed at a later stage because of social issues, such as poor access to health care that may prevent regular checkups with a doctor. Later diagnosis means fewer treatment options.

But African-American women, particularly those who are premenopausal, are likely to get the aggressive triple negative tumors, leading many researchers to believe that biology is playing more of a role.

Breast cancer is considered triple negative when it lacks three distinct receptors linked to the growth of cancer cells. Chemotherapy drugs typically target those receptors, making triple negative tumors particularly difficult to treat. Chemotherapy is often the only treatment option and frequently doesn't work well in later stages.

"Some of the risks that we talk to women about may not apply to the triple negative breast cancer," said Vered Stearns, co-director of the breast cancer program at Johns Hopkins School of Medicine. "There may be a difference in the biology of the tumor itself."

Last month, researchers said they had found four genetic types of breast cancer, including triple negative, also called basal cancer. They also discovered that it resembled ovarian cancer. The researchers said the study offered biological evidence to try ovarian cancer treatments on that type of breast cancer.

Researchers also are paying closer attention to whether African-American women respond to treatment differently than other races.

Stearns said there is some evidence that African-American women may not effectively metabolize tamoxifen, a drug that blocks the receptors for the hormone estrogen. Certain types of breast cancer require estrogen to grow.

African-American women also sometimes develop other health problems caused by the drugs used to treat breast cancer and researchers are trying to figure out why.

Mercy Medical Center received a $450,000 grant from Susan G. Komen for the Cure, the parent of Komen Maryland, to study whether African-American breast cancer patients may be more likely to develop heart problems after being treated with a class of drugs known as aromatase inhibitors.

The drugs, used in menopausal women, stop the enzyme aromatase from changing other hormones into estrogen. Lowering estrogen levels in the body removes fuel for cancers that need the hormone to grow.

Lead researcher Lisa Gallicchio said the three-year study could lead to better treatment options for African-American women.

Still, new treatments could be years away. In the meantime, doctors say, the focus also needs to be on making sure women get regular mammograms.

There is some evidence that African-American women may be diagnosed later because they don't get regular mammograms. Some have no health insurance, while others may not trust the medical system or are afraid to find out they are sick.

Ava Queen is one of those women. She avoided getting a mammogram for months despite her primary care physician's insistence that she needed one. The 58-year-old from Baltimore feared the doctor would discover she had cancer.

When Queen finally was tested last year, the doctor found a lump in her left breast. A biopsy confirmed it was stage 1 cancer.

Queen had to have her breast removed and undergo weeks of chemotherapy. Since being diagnosed, she also has coped with depression.

Queen has finished treatment and her hair is growing back. Slowly, she is starting to feel like her old self. If she could revisit the past, Queen said she would face her fears and get a mammogram earlier.

She said new treatments would be wonderful, but she has friends who still won't get mammograms.

"I know if I had gone regularly like I should have that even if I had cancer they would have caught it at such a small stage they would have been able to save my breast and treat me," Queen said. "I think the main thing that we should do is go and get our mammograms every year. They can't treat you if they don't know what is going on."